Roller bearings with braking devices have already been known for a relatively long time. In the case of roller bearing rotating connections on wind power installations, there is a risk of them failing after a relatively short time as a result of grooves being formed in the raceways. This phenomenon is produced in particular by small pivoting movements in order to compensate for the wind direction, which results in the roller bodies sliding on the raceway. In order to prevent this wear, it is known for various measures to be adopted in order to increase the low rotation resistance in roller bearings. In this context, DE 37 25 972 A1 and DE 41 04 137 A1 propose that an additionally circumferential braking device be used. The braking force and therefore the desired rotation resistance can then be adjusted from the outside. One disadvantage in this case is that, in the first case, the braking element can be canceled only when the wind power installation is shut down. In the second case, the braking device is composed of a large number of individual mechanical parts, and is therefore complex to manufacture, and complicated to handle.
DE 19 04 954 B discloses a rotating connection without a rotating journal for mechanical diggers, cranes or the like, in order to support a superstructure, which can pivot, on a chassis. These rotating connections each comprise a single-part rotating ring and a two-part further rotating ring, which is composed of two profiled rings. The two rotating rings are each supported with respect to one another by the balls in a two-row ball bearing, and are equipped with a braking apparatus. The braking apparatuses each have one or more brake-block supports, which are attached to a component which is connected to the single-part rotating ring. This arrangement has the disadvantage that the braking apparatuses are arranged outside the actual bearing arrangement, and therefore occupy additional physical space.
A bearing arrangement of this generic type with a braking function is already known from DE 101 27 487 A1. The radial bearing arrangement shown in FIG. 1 has a grooved ball bearing, in the form of a radial bearing, and a braking device which is arranged axially alongside it. The grooved ball bearing comprises the inner ring, the outer ring and bearing balls which are arranged between the two rings in a cage. Furthermore, the grooved ball bearing has two sealing rings, which seal the annular space on both sides from the environment. The braking device has an inner holding ring and an outer holding ring. A brake disk is attached via a flat wire spring to a flange, which is directed radially outward, on the inner holding ring, with the brake disk being composed of a ferromagnetic material and having a brake lining on its side facing away from the flange. The attachment by means of the flat wire spring results in the brake disk being connected to the inner holding ring such that they cannot rotate with respect to one another, but such that it can be moved in the axial direction. An opposing surface is formed opposite the brake lining on the outer holding ring, against which the brake lining is pressed during braking. The outer holding ring furthermore has an electrical coil and one or more permanent magnets which are each arranged in the area between the brake disk and the grooved ball bearing, and are mechanically connected to the outer holding ring, and therefore also to the opposing surface.
This has the disadvantage that the braking device must be flange-connected to the bearing as an external part in the axial direction, and therefore occupies additional physical space. The holding rings are of relatively complicated design and must first be connected by pins to the bearing rings in a complex manner. A further disadvantage results from the fact that the braking effect is initiated by a permanent magnet, which attracts the brake disk. In certain applications, however, a continuous magnetic field is disadvantageous since, in some circumstances, dirt containing iron is attracted from the bearing.